4 1/5 divided by 2 4/5 =
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Answer:
We can conclude that the room temperature on Saturday was 24°C
Step-by-step explanation:
For a set of N values:
{x₁, x₂, ..., xₙ}
The mean of the set is calculated as:
In this case, our set is the temperature of 7 days (so we have 7 elements)
{T₁, T₂, T₃, T₄, T₅, T₆, T₇}
Such that:
T₆ = temperature on Saturday
T₇ = temperature on Sunday.
We know that:
"The mean room temperature from Monday to Saturday is 25°C"
Then:
"the mean room temperature of Saturday and Sunday is 28°C"
"The mean room temperature from Monday to Sunday is 26°C"
So we have 3 equations.
Let's rewrite:
T₁ + T₂ + T₃ + T₄ + T₅ = A
Then we can rewrite our equations as:
Removing the "Celcius" and multiplying in the 3 equations by the denominator on both sides, we get:
A + T₆ = 6*25
T₆ + T₇ = 2*28
A + T₆ + T₇ = 7*26
We now need to solve that system for T₆
The first step is to isolate one of the variables in one of the equations, (because we want to solve this for T₆ , let's not isolate that one). Let's isolate A in the first one:
A = 6*25 - T₆
A = 150 - T₆
Now we can replace this on the other two equations:
T₆ + T₇ = 2*28
(150 - T₆ ) + T₆ + T₇ = 7*26
Now, let's isolate T₇ in the top equation to get:
T₇ = 2*28 - T₆
T₇ = 56 - T₆
Now we can replace this in the last equation to get:
(150 - T₆ ) + T₆ + (56 - T₆) = 7*26
Now, we can solve this for T₆
150 - T₆ + T₆ + 56 - T₆ = 182
-T₆ = 182 - 150 - 56
-T₆ = -24
T₆ = 24
We can conclude that the room temperature on Saturday was 24°C